declare module "xmlhttprequest" {
  export class XMLHttpRequest {
    open(method : string, url : string, async : boolean);
    send(payload : any) : Function;
    setRequestHeader(key : string, value : string) : void;
    onreadystatechange : Function;
    withCredentials: any;

    ontimeout: Function;
    onerror: Function;
    onprogress: Function;
    onload: Function;
    abort: Function;

    responseText: string;
    status: number;
    readyState: number;
  }
}